Refractory curved arch



1929- l. HARTER ET AL REFRACTORY GURVED ARCH 2 Sheets-Sheet 1 I Filed Nov. 14, 1925 I VENTOR5 91446 By MA ATTORNEYS owzs, 1929. 1. HARTER ET AL REFRACTORY CURVED ARCH Filed Nov. 14, 1923 2 Sheets-Sheet 2 9 z 2 INEENTOR5 Patented a. 29, 1929 TED TES ISAAC HARTER, or DONGAN firin s, new YORK, ans lu i'rnolui 30mm, or

JERSEY CITY,

New JERSEY REFRACTORY CURVED ARCH:

Application filed November 14, 1923. Serial No. 674,620.

Our present invention relates to refractory arches such as maybe used for the roofs of heating chambers, furnaces or the like, and particularlyto such arches which are subjected to high heat'and to considerable variation in temperature.

One of the great di'lficulties with such arches as heretofore made, has been that, because of the presence of bonding material between the several bricks constituting the arch, the bricks 'are'held'm'ore or less fixedly in relation to each other, so that as the arch is alternately heated and cooled, and particularly if, for any reason, parts of the arch are heated to a greater temperature than other parts the arch has been destroyed, because of the strains produced therein by the conditions just mentioned.

We have found that many of these difficul'ties may be overcome it the arch be made up of refractory brick laid up without any bonding material, such as cement, and with the refractory bricks having a smooth side surface in contact with each other, such arrangement producing an "arch which is ca-pabl'e of sustaining loads and yet in which the bricks are free to move with respect to each other to adjust themselves to relieve undue strains which maybe produced by heating or excessive changes in temperature of the arch.

In the ani'iexeddrawing, Fig. 1 is an illustrative form ofone embodiment of our arch, as such arch would appear in a cross-section of an oven or furnace for which such arch I would provide a roof, only a portion of the side walls or piers providing abutm'ents for the arch being shown, because they form no part of our present invention and obviously may be widely varied; Fig. 2 1s a diagram 40 showing the positions which the individual brick s or members of the arch tend to assume when highly heated," and Fig. 3 is a view similar to Fig. 1 showing a modification.

It will b'e und'erstood that the illustrative arches may beof any length; but since'our invention will be fully illustrated by an arch formed of a single course of bricks,wehave not illustrated the lengthwise View of the arch or of the roof of which such an arch 'may form 0 a part. m r

In Fig. 1 -we have illustrated an arch formedof refractory bricks 10, each preferably being ground on its side faces to produce a smojoth surface, and also to produce, with considerable exactness, the correct angle, so that, when the bricks are laid up in place, their faces will contact to form an'a'rch in the usual manner, with the end bricks abuttinge-gainst a suitable abutment, such as a I skcwback 11. It will be obviousthat, because of the absence of any cement between the bricks, the bricks must be ground to considerable accuracy, because there is no possibility of taking 'up'the usual inaccuracies in such brick by means of more or less cement; It will be understood, however, that accumulated errorn'iay be taken up by cement applied between the end brick and the abutment or re'g'rinding the end'bricks. Theillustrated structure isprovided with supports to prevent lateral movementof the abutments 11 consisting of coltu'nnslt spaceda't intervals opposite columns being connected by a tie-bar 15. A plate 1601* a channel running longitudinally of the kiln is used on either side to retain thereon a cover to be described in greater detail hereinafter. With the arch formed as just described; it will be obvious that as the arch is heated the bricks thereof will expand and the increaSe eO of length in the arch must be accommodated by the arch rising as is shownfi'n Fig; 2. The radius of the top surface ofth'e arch will then he so great as'to necessitate the bricks separating at the top as is shown in said figure. By setting the bricks without cement it willbe seen they are thus free to adjust themselves and undue strains therein will be revented. I I

, Where the arch is us'ed under conditions in which themelting point of the refractory may be exceeded somewh tbn the underside of the arch adjacent the heat wi thout this excess temperature being sufficient to heat the I entire arch to the melting point so as to cause it to falh'th'ere is a possibility that the lower ends of the several bricks will be softened and they will then contract at these lower circle,

which, in turn, lfoiglitcontr'act the lower part of thearch suificiently to permitto tall. 0

To obviate this danger, we may grind the side faces of the bricks 10, so that the angle between these side faces will be slightly less than the angle formed between the lines extending from the center of thearch to the lowermost corners of the bricks. In other words, we may grind the faces of the bricks 10 so that, when laid in the arch, there will be slight spaces (possibly not more than the thickness of a sheet of paper) between the outer ends of the bricks while the inner ends are directly in contact. In other words, the full lines of Fig. 2 which show the position of the bricks when heated also show in an exaggerated way the initial position of the bricks when so ground. Vith this arrangement, if the lower surfaces of the arch contracts, the spaceprovided will permit the arch tosettle as a whole until this space is taken upbut without permitting the arch to fall. In other words, by making the angle between the side faces of the bricks Som what less than the theoretical angle necessary to form the desired arch, we provide a means by'which destruction of the arch will be prevented even if the changes on the lower face of the arch are such as would otherwise cause the arch to fall.

Preferably the outer surfaces of the bricks 10 are provided with a cover. This may take the form of a layer 12 of refractory insulating material, such as grog, crushed refractory brick and the like, over which there may be placed a layer of insulating brick 13. Or the layer 12 may consist of a monolith composed of refractory material, such as highly calcined kaolin, bauxite or mixtures of the two. The cover may be formed by covering the brick 10 by a sheet of paper or other carbonizing agent and then spreading thereover a plastic mass composed of the calcined refractory material referred to, together with ground unburned material of the same refractoriness to act as a. bond. To insure further and initial bonding action, a small amount of a temporary binder, such as glucose or molasses or the like, may be also incorposame time, to help cool the arch.

rated in the plastic mass. When the arch is subjected to its first burn, the paper and glucose for example are burned out and the particles of the monolithic mass are bonded together by the effect of the heat. In case the tops of the brick 10 are slightly separated,

the cover 12 serves the usual function-of keeping out foreign matter from the spaces between the brick. The monolithic cover may or may not have an additional layer of insulating brick 13, as desired.

In Fig. 3 we have illustrated a modification of our novel arch arranged so that air ducts extending along the arch may be formed. such ducts being used to heat air for various industrial purposes, and, at the Ihe arrangement shown in Fig. 3 is substantially the same as that shown in Fig. 1, so far as the formation of the arch proper is concerned, but, in this form, certain of the refractory bricks, as at 17, are made longer than their fellows, so as to form spaces above the normal heightof the roof and between the projecting ends of the bricks 18. A cover 18, preferably monolithic, is laid over the ends of the bricks 17, this monolithic cover being made in a manner described, except that, of course, in this case a more substantial support across the ends of the bricks 17 will be necessary for the plastic material, such support being conveniently formed of wood which would burn out in the oxidizing atmosphere. In order to prevent foreign matter from falling between the bricks 10, 10, particularly when such bricks are made with openings between their uppper ends, we may provide covers 19 which may be monolithic and which, of course, function precisely the same as the cover 12 of Fig. 1, except that each cover 19 extendsover the lowermost bricks in the arch.

It will also be-understood that by the expression smooth faces as used throughout the specification and claims, we mean that the surfaces of the brick faces are smooth to the touch, i. e., are relatively free from irregularities, whereby each brick when cold at least may have a substantial contact with its neighbor and not that each brick face is necessarily all in one plane.

We claim: 7

1. A curved arch comprising refractory bricks, each brick having its sides tapering toward the center of curvature of the arch and each side face of each brick near its narrow end in direct contact with the corresponding side face of an adjacent brick and near the narrow end of the brick with the corresponding side face of an adjacent brick and free to slide thereon, the side faces of the bricks distant from the inner curved side of the arch being separated from each other.

3. A curved arch adapted to extend over a heated space,said arch comprising refractory bricks having smooth side faces in substantially single planes and directly'in contact with the side faces of adjacent bricks, the side faces of each brick, when the arch is 0001, making an angle with each other slightly less than the angle between the lines joining the inner edges of the bricks with the center of the arch.

4:. A curved arch adapted to extend over a heated space, said arch comprising refractory bricks having smooth side faces in substantially single planes and directly in contact with the side faces of adjacent bricks, the side faces of each brick, when the arch is cool, making an angle with each other slightly less than the angle between the lines joining the inner edges of the bricks with the center of the arch, and a monolithic cover for at least a part of the arch extending over the outer faces of the bricks and independent of the bricks.

5. A curved arch comprising refractory bricks with each side face of each brick near the inner curved side of the arch in direct contact with the side face of an adjacent brick, the side faces of the bricks distant from the inner curved side of the arch being separated from each other, some of the bricks projecting upwardly above the top of the arch to form passageways extending along the arch, and a cover for such passageways resting on said projecting bricks.

6. A curved arch comprising refractory bricks with each side face of each brick near the inner curved sideof the arch in direct contact with the side face of an adjacent brick, the side faces of the bricks distant from the inner curved side of the arch being separated from each other, some of the bricks projecting upwardly above the top of the arch to form passageways extending along the arch, and a monolithic refractory cover for such passageways resting on said projecting bricks. i

7. A curved arch adapted to extend over a heated space, said arch comprising refractory bricks having smooth side faces in substantially single planes and directly in contact with the side faces of adjacent bricks, the side faces of each brick, when the arch is cool, making an angle with each other slightly less than the angle between the lines joining the inner edges of the bricks with the center of the arch, some of the bricks projecting upwardly above the top of the arch to form passageways extending along the arch and a cover for such passageways resting on said projecting bricks, and refractory covers for the bricks between said projecting bricks arranged to extend over the outer faces of the bricks.

ISAAC HARTER. ANTHONY M. KOHLER 

